randall



Feb. 28, 1928.

K. C. RANDALL SIGNALING SYSTEM Filed July 11, 1924 3 Sheets-Sheet 1 I FI I I I M I'I WH I I I I I INVENTOR Kar/ C. Randcfl/ WITNESSES: ,4 j M ATTO EY Feb. 28, 1928.

K. C. RANDALL SIGNALING SYSTEM Filed July 11. 1924 I5 Sheets-Sheet 2 OMK N INVENTOR Kar/ G Aanda/l WITNESSES;

ATTORNEY Feb. 28, 1928. 1,660,886

4 K. c. RANDALL S IGNALING SYSTEM Filed July 11, 1924 :s Sheets-Sheet :s

0/ mvsmor: WITNESSES:

] mam Kar/ Cifiandafl 9/ ATTORNEY Patented Feb. 28; 1928.

ITED TAT S PATENT OFFI E.

KARL C. RANDALL; OF EDGEWOOl), PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURINGCOMPANY, A CORPORATION OF PENNSYLVANIA.

' S IGNALING sYs'rEM.

Application file'd trul 1 1,

My invention'r'elates, in general, to sig-' naling systems and more particularly to means for-supervising, from a central point, the operation of'elcctrical equipment in a remotely-disposed station or substation. "'Oneobject of my invention is to'pro'vide means whereby a dispatcher at a central station is ableyt'o' see a substantially simu'l: tancous' reproduction of the operation of the remotely-disposedelectrical apparatus.

Another object df niyinvention is to pro- "ide an improved television system that shall be applicable for enabling the'dispa'tcher'to observe the function of electrical" equip mcnt'in a reinote" station and ascertain the indication of meters, the operation of electric generating:machineshetc;

Another vobject of my invcntion'isto pro vide a device at the statibn that'may b controlled fromflthe' dispatchers to cause the television-"apparatus 'to'i transmit an image of any desired portion of the station or apparatus .unit therein;

"A'Still further object of my invention is to provide improved circuits for a'group of relays that are used incontrolling the device mentioned the preceding paragraph.

The above and other objects of 'my inven tion will be explained more fully hereinafter with reference to the accompanying drawings forming apart of this specification.

Referring now to the drawings, Figure 1 is a diagramof the transmitting television apparatus at the stat-ion. V

Fig. 2 is' a diagram of the'receiving televison apparatus at'the dispatchers office; an

Fig. 3is a View of the apparatus and circuits for selecting the desired apparatus so that its image may be transmitted to the dispatchers office. i

Both the apparatus in the dispatchers office and the apparatus in the station are shown by means of conventional circuit and apparatus diagrams in sufiicien't detail to enable my invention to be re'adilyexplained and understood. p v c The apparatus of the transmitting set 1 at the station comprises an antenna system 3 that is so tuned that it may oscillate at two separate and distinct frequencies. The antenna-3 is disposed below a power circuit 130' which extends to the dispatch'ers oflice. The radiations emi d from the an nna 3 1924. Serial N0. 725,354.

tenna 3, is'conneeted on one-side by means of a transformer 4 to the plate. circuit of an amplifier triode 5; The rid of the amplifier 5'is connected through atransfori'n er 6 to the plate circuits-of modulator triode's 7 and 8. An oscillator 'triode 9 is connected through a transformer '10' to the grid circuit of the modulator triodes 7 and 8. i The above arrangement comprises what is known as an ordinary push and'pull transmitting arrangement.

By means of a-transformer'l'lfthe plate circuit of"an amplifier 123's also connected to the grid circuitsofi the modulator triodes 7 and Theoscillating ci'rcuit comprising the antenna; '3 "also 'o'nrie'ctedfby m ans a transformer 13,"tol .the plate dre mer an ampli fier triode 14." The grid circuit of the amplifier 1 t is'- conne'ct'ed, by means of 'a transformer 15,' to the platelcircuitsjiof modulator triodcs 16 and 17. An. oscillat or triode'18 is connected, by means of a transformer 19, to thegrid 'circuits.of tlie' modulatortriodes 16and 17. By means of transformers 20 and 21, alternating-current generators 22 and 23'a-re also connected to the grid circuits of the modulator'triodes 16 and 17.

The generator 22is so constructedas to generate high-frequency alternating current of a frequency of about 1000 cycles; while the .alternating-currcnt generator '23 is adapted to generate an alternating current of a frequency of about 16 cycles. I

It is, of course. obvious that triodes connected in oscillating circuits may be used in place of the alternating-circuit generators 22 and 23.

The plates 25 and 26 in a cathode-ray'tube 27 areleonnected in the circuitthrough a series transformer 24. Coils 28 and 29 are associated with the cathode-ray tube 27 in such position that the magnetic field which may be produced by said coils is parallel to the electrostatic field which may be gen:

is substituted a com )osite late b2 havin l n layers of different material. The plate is placed in theglass container of the cathode ray tube in such manner that there is a portion 33 at the end of the tube which is sealed from the remaining portion. The plate 32 is constructed of a thin sheet of aluminum foil 34 which may be about .0001 mieron'ieters in thickness. upon which is. placed a layer of aluminum oxide, the. thickness of which may. be about .0003 micrometers. Upon this is placed a layer of alkali metal 36 which may be potassium hydroxide, or other photoelectric material. The whole of the cathode-ray tube 27 is tilled with zi'rgon Vapor at low pressure.

A lens 37 or system of lenses is secured in place by means of a frame 38 disposed at the=end of the cathode-ray tube. The lens 37 is arranged 'to focus the image or scene that is reflected from a mirror 42 upon the photoelectric metal of the composite plate 32. A gird 39 is placed at some distance in front of the composite plate 32 and is connected to the grid of the amplifier triode 12. A high potential is applied to the anode 31 by a rectifier 40 which is supplied with cur- ,icnt from an alternating-current source 41.

In the receiving device 2, an oscillating .circuit 50, including an antenna 51, is

adapted to be resonant to current of two distinct frequencies, these frequencies being the frequencies generated by the oscillating circuit-s that include the triodcs 9 and 18 of the transmitting set. The antenna 51 is also disposed below the power circuit- 130 so thatit may be affected by the C21I'llQP-(tll'lCHt radiations in the circuit. An amplifier triode 53 is connected to the oscillating circuit- 50. The plate circuit of the amplifier triode 53 is connected to a grid 54 in a cathode-ray tube The cathode-ray tube 55 constructed in a. manner similar to the ordinary cathode ray oscillograph and comprises a hot cathode 56, the grid 54, a tubular anode 57. plates 58 and 59 that are used to set up an electrostatic field and a fluorescent screen 60. The anode 57 of the cathode-ray tube 55 is supplied with high voltage by the operation of arectifier 61 that rectifies the alternating current supplied by a source of. alternating current 62. t

The oscillating circuit is also connected by means of a transformeiytil-l to a circuit 64. The circuit 64 is,'in,turn, connected by means of transformers 65 and 66 to the grid circuit of the amplifier triodes 67 and G8. The plate circuit oft-he amplifier triode 67 is connected to the plates 58 and 59 of the cathoderay tube 55, while the circuit of the amplifier triode 68 is connected to the coils (39 and 70 that are associated with the oathode-ray tube and so disposed with res )ect thereto that the magnetic fields generate by the coils are parallel to the electrostatic field generated by the plates 58 and 59. r I V v The transformer is so constructed that it acts as a wave trap for theparticular high frequency that-is generated by the generator 22 at the transmitting stationso asto eliminate this frequency fromthe circuit 64. In a like manner. the transformer 66 acts as a wave trap for the particular frequency generated by the generator 23-by the transmitting station. In Fig. 3,.a calling device CDj'and a key- K are located at the dispatehers otfice. .The calling device CD may be. of. anyordinary and well-known type and its function is to interrupt the circuit, includingeonductors and 71, extending'betweenthe dispatchers oflice and station. The key- K may be of any ordinary and well-known type which functions, when operated;v to complete the circuit including the conductors 70 and 71 and a line relay 72 at the station. The relay 72 at armatures 73 and 74 controls the circuits of the slow-acting relays 7 5 and 76. Relays 77 to 83, inclusive, are of the usual type and control the operation of a device 8-1. The relay 76 controls a circuit for a relay 85.

The device 84, referringto Figs. 1 and3, comprises a flat metallic disc 87 that carries an insulating segment 88 near its circumference. The .disc 87- is engaged by brushes 89 to 94,.inclusive, which are equally spaced about the-circun'iference of the disc. These brushes are adapted to restupon the metallic disc and are so positioned that, as the disc 87 moves, the insulating segment 88 is adapted to bring any one of thebr ushes from contact with the metallic disc. The disc 87 is adapted to be driven by a gear that. is operated by a worm 96 on a shaft- 97. There is a shaft 98 mounted upon the disc 87 to which is mounted the mirror 42. A disc 99 is attached to the shaft97. The disc is adapted to be drawn into engagement with a disc 100 that is driven by a motor 101 by the operation of a magnet 102. lVhen the magnet 102 is energized, the disc 87 is rotated, as is the mirror 42.

The whole device 84 is so positioned with respect to the transmitting cathode-ray tube 27 that the objectire of thelens 37 falls upon the mirror 42, as hasbeenindicatedin the drawing. As the mirror 42 rotates,

loo

it' is adapted to reflect the desired Views of the apparatus in the substation." For .instance, ln one {Sositioxiof 'the'mirror 42, it is adept ed' to reflect the' inia ge of the meter 1'03 and, inanoth'er position, an image of the generating 1nachine' 101. Of course, other electrical apparatus, ,a's'ivcll as a general View of x iarious portions of the substation, Inaybe reflected by .tlie mirror '42 1 f Having briefly ildescrihed the apparatus 's'iiiwn in he; iengs 1 mnnrm explain its xletail edioperationff For this purpose, it krill hefassunied that the dispatcher desires to sceitain the reading ofitli'enrcter 103. er to accomplish th is" result, it is iiecessar y for the ini'rro'r j4 2 infthe substation t6 b i u f P 9 h jl i en iinag'hf the facedenigrate-103. At the dispatchers ofii ce the disposition of 'tliefjn irror Till be assigned a, certain .d fi r tt i i l r I i llfbfi fi ms that this number in 'thee presnt' 'instance.

" I n case the dispatcher des'ires'toibr'ing the mirror'1 12 into a'nyotlierpositio n, a digit other-than Zirvill "be dialedl In accordance with this operation,s'orne oftherelays in .the' relay group comprising the relays 77 to manner "as before i jw i th substantially il' r re n t hh A InI r deif to obserVetl're operation of the trlf'the d pa he will-oper the key K; Band will then I operate the "calling device CD' in accordsnceiqw ith the digit 2. When the key K closed, circuit is completed for 'the ili nejrelay 72} mo substation over the trunkfcQhdlictol sfmland =71. The relay 72-5 i bin fine s -f d pl esi cuit forthe slow-iacting relay 75 fat armature 73,.andat1a'r1natur74 open the circuit of the slow ac ting relaylj76 'l he 'i elay 76 will noiv b'e dcenerg'i'zed before the dispatcher has'opeigated his calling dc'vicel'f. 'lhcrelay 75, upon being energized, p repares a circuit for the relay 77 at armature 105 andia t armature 106 prepares locking circuits-for thef-rela'ys" 78 tof83, inclusivc. \Vhen l the calling dc'viceCD is operated, two interruptions .are' produced in the circuit of the line. relay 72' and this relay retracts its armaturetwice. .By the-operation of the armatur A74, ih fslowmcting relay 76 is maintained erie-rgizei '1 i Upon the retraction of the arnia'tnre 73,121 circuit 'isl corripleted extending from ground ,by fay io f said 'falrnratnre. {1nd its back contact, armature 105 and its ji ron t contact, normally closed springs controlled by armature 107, a'r n1ature, 108'and its back n acfif rm i e' 9"a 1..1 t =1. se arrnature 110 and its contact, armature 11 1 and its back contact, a r1natur e 112 and i back .ic' tat; nrm t r 3f= fit i ack. cortacfifand relay77 tojba ,ery.

The relay 77 is energiz ed toopeh its orig inalenergizingcircuit by theoperation of armature 107 shortly after it has completed a locking circuit for itself at the front contact of this armature over a portion of the previously traced circuit. Another result'ot' the operation of the relay 77 is that, at armature 114,4 circuit is completed for the relay 78. The relay 78 is energized to 'coinplete'a locking circuit for'itself at armature'-115,to open its original energizing circuit at'this arrnn'turc and to place ground upon brush 92 at armature 11G. i

hen the relay -72"i s -energized =afterv its first dcener'gization; the-circuit of'thcrelay 77-'is opened. and this relay 1 is; deenergized. Th'ejrelay 78 remains opera-ted by reason of its locking circuit which extnd's from ground by way; of armature 106 {and its front contact, normally closed springs controlled byflarm'ature 117,13;rma't ure' 115 and its' front contact and r'elayj78 to'batteryi' Now, when' th'e armhtuie-73jis' again retracted, there is fa circuit; completed which extends 'from' ground-byjray'fof said arma ture and its back' contact; armature 105 and its front contact,"norn 1ally' closed springs controlled by armature l07,='farmature '108 and its front contact, normally; closed springs controlled by armature 118'andvrelay 79 to' battery. p The relay 79 is eiierg'i'zed to' open its original energizing circuit-at a'rrnatur'e 118, and to establish another flocking circuit for itself at 'the front Contact of'this 'armat ure which'extends to the nom nally closed springs controlled. byj 'arrnajtn re' 1119 to ground by way". of :front c'ontact aii'cl zi'rma'tuifc 1061 Othc r results of the operation of the relay 7 9 arethat a circuit is prepareclffohthcrelay 80,.at'arma'ture 109, and at ,ai'maturc 120 g'ro'und'is placed upon 'thel'brush flfi, 'The' relay 78 is not clecnergizedhvhcn its locking circuit is opened by: reason of the fact that another circuit is c 'oi npleted for it which. extends from ground byway of armature 73 and its back contact, armature 105 and'its front contact, armature 1 15 and. its front contact and relay 78 to battery. Howvcnivhen the relay 72isagain energized, the. circuit for the relay "78 is'opened and this relay is (leenergized topreparc a. circuit or the relay 80. The relay 79 remains encrgiz edby reason of its locking circuit previouslv traced. i

The'slow acting' relay 76 is I'na-intained energizcd during'the intermittent operation of the line relay"72. However, after these two interruptions in the'circuit'of the relay '72- have been produced by thc'opera tion of the calling deviceCD, the relawe remains permanently energized and the circuit of the relay 77 1s consqfi'enng Openedfor asufiicientinterval of time "to permit this relay to.deenergize; As a :result of this operation, a" circuit is completed which extends from &

battery by way of back contact and armature 122, relay 85, brush 121, metallic disc 87, brush 93 and armature 120 and its front contact to ground.

The relay is energized over the above circuit with the result that the circuit of the motor 101 is closed in an obvious manner at armature 123, while, at armature 124, a circuit is completed which extends from ground by way ofsaid armature and its front contact and magnet 102 to battery. The-motor 101 is immediately started to operate. The magnet 102 is energized to bring the disc 99 into engagement with'the disc '1-0O.with the result that the worm 96 drives the gear 95.

The-disc 87 is rotated until the insulated segment 88 is brought under the brush 93. By this operation, the circuit of the relay 85 is opened and thisrelay is immediately deenergized to open the circuit of the motor 101 and also the .circuit of the magnet 102. By the deenergization. of the'magnet 10.2, the movement of the. shaft 97 ceases, as does the rotation'of the-disc 87. During the movement of the disc .87, the mirror 42, which is attached: tdthe shaft 98, is rotated. into proper position-so that it reflects the image of the meter 103. Y

A suflicient interval oftime having elapsed to bring about the operation of the device 84', the dispatcher .will restore the key Kto normal, therebybringing about the deenergization of the line relay 72 and the slowacting relay 75. By the deenergization of the slow-acting relay 75, the locking circuit of the relay 79 is opened and thisfrclay is restored to normal. The relay 76 is ener-. gized to open another point in the circuit of the relay 85.

All thecontrol apparatus is now restored to normal. and may be operated by'the dispatcher to bring the mirror 42 into. a position so that it reflects the image of another portion of the station.

It will be seen, as shown in the drawings, that the mirror 42 has but six positions, corresponding to the six brushes .89 to 94, inclusive, resting on the disc 87. The number of positions may, obviously, be increased indefinitely by the addition of more brushes and more relays, such as 78 to 83, inclusive.

The dispatcher has now brought the mirror 42 into the proper position so that the lens 37 of the transmitting device focuses the image of the metering device 193 upon the grid 39 and upon the composite plate 32. The operation of the television transmitting apparatus will now be described Ordinarily, the oscillations generated by the oscillator 9 are not radiated by the antenna This is because of the fact that these oscillations-are neutralized by the action of the modulator triodes 7 and 8, and, consequently, there'is no transferoi .ener 111w w de w t ansferee" only manner in which the antenna can be set in oscillation by the operation of the triode 9 s by nge n con it o n. the Pr ary of the transformer 11 which is connected to the grid 39 and to the aluminum foil 34 of the composite plate 32 The light from the image placed before the lens 37 is so varied that, upon the focusing of this light upon the photoelectric; material 36 0 th mpos t -Plat 2-, e ron m sion of varying intensity by this substance takes place in accordance with the'li ht from the object-placed beforeihe lens 3 This electron emission maybe considered a species of conduction between the photoelectric material 36 and thegrid 39. Thisphenomena is'intensifiedfhy the argon vapor thatfills the container 33 as a resultof the ionization of the vapor, H Q

In view of the fact that the aluminum oxid P ate 35 is ns ator, tlie m? electrical nnection exis ng between t rid 43. and t a umi um Plate 5, e though the photoelectric material emits elecron Wh n h cat o e; beam ke particular point upon thealuminum foil, it is of suflicient' intensity to penetrate it, as w l 's' l e uminumbx d Asa re of h pe r ugh. he Par cu a P int that is covered by the cathode beam, there is c tion betw enhe a um n m Plat 34 i and th gr d 9- .Th curr nt fl w ng t circuit is amplified by means of the amplifier r d The' u put o t e amp 12 now causes 'the modulator triodes 7 and ,um

8 to transmit, through the transformer 6, the high-f q y ci la ons. gener t d by t oscillator triode 9, modulated in accordance with the current in the amplifier triode 12 which, in turn, is overned by the intensity of the lightfocuse upon the particular spot at which the cathode ray is located. The intensity of this electron stream is, of course, governed by the intensity of the light reflected from theobject.

As previously mentioned, the alternatingourrent generators 22 and 23 are producing alternating current of a high and low frequency, respectively. By the operation of the mod lator triodes 16 and 17, the oscillations produced by the oscillator triode 18, are modulated in accordance with both the frequency of the alternating current generated by the generator 22 and the alternating current gener ted by the generator 3- Tl i modulated h gh i eq eii y w a tis am fi y the amplifier .triode l4 radiated by "the ntenn fi- A s the output of the alternatingcurrent g nerato .22 -a s0 m ated to't Pla e 2 and 6 in th sathad -mrti e 2 21 1 os tie fi ld i se p by t ese P at s wh anes i --a. c dan. i 'ivit the trai ees) Of the u n ratedfby the g nerat r 2 tkufileaasstatia field a s he s ee static action upon the electrode beam causes it to be swung from one side of the composite plate 32 to the other.

A portion of the alternating current generated by the generator 23 also traverses the coils 28 and 29 which, as before mentioned, are so positioned with respect to the cathode tube 27 that the magnetic field generated by these coils is parallel to the electrostatic field generated by plates 25 and 26. The varying magnetic field set up by these coils tends to cause the cathode-ray beam to traverse the plate 32 in a direction at right angles to that before described.

. The resultant action between the magnetic fieldsuandthe electrostatic fields upon the cathode beam is such that the beam covers every pointin the ,whole area of the composite plate 32 in of a second, that is, in l/ cycle -.of the frequency generated by the alternating-current,generator 23. Thus, in ofa second, the cathode beam traverses the surface of the composite plate twice.

the cathode beam traverses the surface of the composite plate 32 point by point in a definite sequence, there is a current flowing fromthe grid 39 and the aluminum foil 34 at each particularpoint, and this current is diiectly proportional to the intensity of li ghtre flected from the object to be observed. Thus, theoscillatiug current generated by the oscillator triode 9 is modulated in accordance with the light from each portion of the image. p

At the receiving station, the modulated oscillatory currents generated by the oscillator 9. of-the transmitter are received by the antenna 51 and transferred to the detector triode 53 through the transformer 52. The detector triode 53 then operates to detect the modulations .andthen these are transferred through its platecircuit to the grid 54 of the cathode-ray tube 55.

By means of the transformer 63, associated with the oscillating circuit 50, the modulated radio-frequency current generated by oscillator 18 is received and transferred by transformers 65 and 66 in the detector triodes 67 and 68. Bythe operation of the transformer 65, only the radio frequency that is modulated by the generator 22 is detected. In a'like manner, by the operation of the transformer 66, only the radio frequency modulated by the generator 23 is received by thedetector triode 68.

As the plate circuit of the detector triode 67 is connected to the plates 58 and 59 in the cathode-ray oscillograph 55, an electrostatic field is set up by these plates which varies in identically the same manner as the electrostatic field generated by the plates 25 and 26 in the. transmitting "cathode-ray tube. Likewise, the plate circuit of the triode 68 is connected to the coils 69 and 70 which generate a magnetic field parallel to the electrostatic field generated by the plates 58 and 59 and that varies in exactly the same 1nannor as the magnetic field set up by the coils 28 and 29 at the transmitting station. Thus, when the cathode-ray beam passes through the grid 54 and the anode 57 to the fluorescent screen 60, it is caused to traverse a path in accordance with the resultant magnetic and electrostatic fields set up. Therefore, the cathode-ray beam traverses the whole area of the fluorescent screen once in of a second, or twice in of a second, in. the same manner as the cathode beamin the cathode-ray tube 27 at the transmitting station.

WVhen the cathode beam in the cathoderay tube of the transmitter is in a certain particular position, the oscillating current generated bythe oscillator!) is modulated in accordance with the intensity of .theilight falling upon that particular point. This modulated current is radiated by the antenna 3 and received by the antenna 51 at the receiving station. At this particular point, the cathode beam in the cathode-ray tube 55 will be in the same relative position as the cathode beam at the sending station. By the action of the grid 54, the intensity of the cathode ray reaching the fluorescent screen at this particular point is varied in accordance with the light from the image at the transmitting station.

Thus, for every particularpoint on the image, the carrier currentradiated by the antenna 3 is modulated whereby the poten tial on the grid 54 of the receiving cathoderay tube 55 is varied, as is ,.also, the intensity of fluorescence of the particular point upon the fluorescent screen 50.-

As the whole area of the composite plate 32 at the transmitting station and the fluorescent screen 60 at the receiving station is covered by the cathode beams in 3 of a second, the image of the object will be displayed on the screen 60 during of a second. However, as the frequency of the oscillation of the generator 23 is 16 cycles per second, the picture will be transmitted twice and will remain on the screen 60 during of a second. Thus, 'due to the persistency of vision phenomena, any movement of the meter before the lens 37 will be. prop erly transmitted and recorded upon the fluorescent screen 60 and will appear thereupon as a moving image.

It will be seen that the indication of the meter 103 will be produced upon. the fluorescent screen 60 and, as a consequence thereof, the dispatcher is able to ascertain the indication of the meter.

In the same manner as above, the dispatcher may control the device 84 so that the mirror 42 is adapted to reflect an image of a generating machine 104. The image of this machine will be transmitted in a manner similar to that above described. If this generating machine is sparking excessively at the commutator, the dispatcher will be apprised of such fact in the same manner as if he were present in the station.

, In substantially the same manner as above, any operation of the substation may be observed by the dispatcher and he may thus ascertain the functioning of any electrical equipment therein.

In the ease described, the beams in the cathode-ray tubes'are operating all the time, as are the oscillating circuits and other associated apparatus. It will be apparent that this is unnecessary and thatthe apparatus may be so arranged that the apparatus will be functioning only so long as the'key K is operated at the dispatchers office and the relay -is energized at the 1 bfi m n the system-just described, thetelevislon apparatus at the substation and dispatehers office are operated by carrier current over the pwer circuit 130.' It is obv ous, of course, that the communieatijonbetween stations may be obtained by ordinary space radio. I

My invention is not limited to the hparti'cular arrangement of the apparatusillus trated and described, but may be variously modified Without departing from the spirit and scope thereof, as set forth in the appended claims.

-- I claima's-my' invention? 1. In a signaling system, the combination with a first s'tat'ion, a plurality of images at said'first; station, a second station, picturetransmitting apparatus at said first station for transmitting images from 'said first to said second station and means for selecting said images to be transmitted from said second station.

2. In a signaling system, a first station, picture-transmitting apparatus thereat arranged to be focused on any one of a plurality of images, a second station remotely di posed from said first. station, and means ineluding circuit arrangements for controlling the focusing ofsaid transmitting apparatus from said second station. Y

3. In a signaling system, a first station, a plurality of devices 'thereat, picture-transmitting apparatus for'translat-ing the images of any one of said devices into electric currents, means for transmitting said currents to remote point's, a-second station for translating said currents into an image, and means controlled from said second station for selecting one of said devices to have its image transmitted.

4. In a signaling system, a first station, a second station, a plurality of devices at said first station, picture-transmitting I apparatus for transmitting the image of anyone of said devices, and means'eontro'lled from said second station for selecting the devices whose image is to he transmitted.

5. In a signaling system, :1 first station, a. remotely disposed station, a picture-transmitting apparatus for translating into electric currents views within its focal range, and means including circuit arrangements whereby any one of a plurality of views are brought within the focal range of said transmitting device.

(5. In a signaling system, a. first station, a remotely disposed station, a picture-transmitting apparatns for translating into electric currents \iens within its focal range, means for translating said currents into views at said second station, and means including ci'rcuit arrangements whereby any one of said views are brought within the focal range of said transmitting device.

7 In a picture-transmitting system, a first station, a plurality ofviews, a second station, picture-transmitting apparatus for trans mitting views from said first to said second station, and means controlled from saidfs'ecohd station for selecting the view to be trans mitted.

S. In a picture-transmitting system, a first station, a cathode ray tube for translating views into electric currents at said first *station, a reflector for reflecting views upon said tube, a remote station for receiving said views, and means controlled from said re} mote station for controlling said reflector.

9. In a signaling system, a firstxstation, a second station, picture transmittin'gapparatus at said first station, and means for selectively controlling the operation of the p ic' ture transmitting apparatus from saidfs'econd station.

10. In a signaling system, a first station, a second station, picture transmitting apparatus at said first station, picture receiving apparatus at said second station, means including said picture transmitting and receiving apparatus, for transmitting pictures from said first station to said second station, and means for selectively controlling the operation of said picture transmitting apparatus from said second station.

11. In a signaling system, a first station, a second station picture transmitting apparatus at said first station, picture receiving apparatus at said second station, a signaling line connecting said stations, means including said picture transmitting and receiving apparatus and said signaling line for transmitting pictures from said first station to said second station, and means forselectiyely controlling the operation of said picture transmitting apparatus from said second station.

12. In a signaling system, afirst station, a second station, picturev transmitting apparatus at said second station, picture receiving apparatus at said second'statiom'a transmit.-

ting medium connecting said stations, means including said picture transmitting and receiving apparatus and said transmitting medium for transmitting pictures from said first station to said second station, and means for selectively controlling the operation of said picture transmitting apparatus from said second station.

13. In a signaling system, a first station, a second station, a plurality of devices at said first station, means for transmitting images of said devices from said first station to said second station and means for controlling said first mentioned means from said first station.

14. In a signaling system, a first station, a second station, a plurality of devices at said first station, means for transmitting the images of said devices from said first station to said second station, and means for selectively controlling said first mentioned means to transmit images of predetermined ones of said devices, from said second station to said first station.

In testimony whereof, I have hereunto subscribed my name this 7th day of July 1924.

KARL C. RANDALL. 

